Plaque is initiated when bacteria adhered to pellicle form a proteinaceous film on the surface of teeth. The adherent bacteria metabolise dietary constituents and reproduce and aggregate to form the tenacious deposit known as plaque. Plaque generally consists of bacteria, bacterial end products such as polysaccharides, inorganic salts and salivary proteins. Plaque bacteria ferment dietary carbohydrates to organic acids which demineralise enamel resulting in tooth decay.
Calculus is essentially plaque that has been mineralised with calcium phosphates salts. As calculus matures and hardens, it tends to stain noticeably due to adsorption of dietary chromagens. In addition to their unattractive appearance, calculus deposits at the gum line are a contributing source of gingivitis and periodontal disease. Besides the hygienic and health problems resulting from plaque, research has shown that the primary source of bad breath is the retention and subsequent degradation of dead cellular material sloughed off continuously by the normal, healthy mouth.
Modern dental hygiene and denture preparations typically contain antiplaque and/or antitartar agents, as well as antimicrobial agents and flavorants. Antimicrobial action could affect plaque formation by either reducing the number of bacteria in the mouth/dentures or by killing those bacteria trapped in the film to prevent further growth and metabolism. Flavorants may alleviate the problem of bad breath via a deodorising action. Some antimicrobial agents, e.g. menthol may, also serve as breath deodorisers. However, the efficacy of antimicrobial agents depends largely on their intraoral/denture retention, particularly their retention on the surface of the teeth or dentures where plaque is formed.
A typical disadvantage of known dental preparations is that only a relatively short time during which the teeth are being cleaned or the mouth is being rinsed is available for antimicrobial agents in the preparations to take effect. The problem is compounded by the fact that dentifrice preparations are used infrequently: most are used once or, perhaps, twice daily. Consequently, the long time period between brushings for a majority of the population provides optimum plaque forming conditions.
There has been a need, therefore, for developing an oral formulation which has a prolonged, residual antimicrobial and/or flavour impact effect.
Oral compositions, if not aqueous themselves, are required to act within an aqueous environment. Many ingredients of such compositions act more effectively if they can first be effectively dispersed within an aqueous medium. Once dispersed, those ingredients which act by depositing on the teeth or other surfaces within, or for use within, the mouth, are then required to be deposited from aqueous dispersion in effective amounts.
There is a further need, therefore, for developing an oral formulation from which active agents can be dispersed into aqueous solution and then efficiently deposited onto teeth, gums or dentures.
It is known to include silicones in dentifrice compositions, allegedly to coat the teeth and prevent cavities and staining. For instance, GB-A-689,679 discloses a mouthwash containing an organopolysiloxane for preventing adhesion of, or for removing tars, stains, tartar and food particles from the teeth. The mouthwash may include antiseptic compounds, such as thymol, and flavouring and perfuming agents.
U.S. Pat. No. 2,806,814 discloses dental preparations including, in combination, a higher aliphatic acyl amide of an amino carboxylic acid compound as an active and a silicone compound. The patent notes that silicone compounds have been proposed for prevention of adhesion or to facilitate the removal of tars, stains, tartar and the like from teeth. The silicone compound is said to act as a synergist in improving the antibacterial and acid inhibiting activity of the active ingredient. Dimethyl polysiloxanes are said to be particularly effective. Flavouring oils and/or menthol may be included.
U.S. Pat. No. 3,624,120 discloses quaternary ammonium salts of cyclic siloxane polymers for use as cationic surfactants, bactericides and as anticariogenic agents.
EP-A-376,363 discloses dentifrices containing amino alkyl silicones and sarcosinate surfactants which form a hydrophobic barrier on the surface of teeth.
Nevertheless, a need still exists for improved oral compositions from which active agents can be dispersed into aqueous solution and then efficiently deposited onto teeth, gums or dentures.
Accordingly, the present invention provides oral compositions, comprising an aminoalkylsilicone, having improved efficacy on plaque, mucilaginous and bacterial deposits and which further comprise a surface active agent chosen to enhance the dispersion of the aminoalkylsilicone, whilst at the same time providing improved substantivity and efficacy on teeth, gums and dentures; together with excellent physical characteristics, and in-use performance characteristics.